But you don't have to. Instead, incorporate some single-leg running into one or two of the runs you're already doing every week. Start by running on just your right leg for 10 strides and then on just your left leg for 10 strides. Gradually increase the number of strides you do on each leg until you reach 30 strides per leg. You will notice that it gets easier to go longer on one leg, which is a sign that your legs are adapting to the stress and your stride is becoming more efficient.
Steep Hill Sprints
If you have never done a steep hill sprint before, you should not leap into a set of 10 of steep hill sprints the very first time you try them. These efforts place a tremendous stress on the muscles and connective tissues. Thus, the careless beginner is at some risk of suffering a muscle or tendon strain or another such acute injury when performing steep hill sprints. Once your legs have adapted to the stress they impose, steep hill sprints actually protect against injury. But you must proceed with caution until you get over the hump of those early adaptations.
More: How to Tackle Hill Training Your very first session, performed after completion of an easy run, should consist of just one or two 8-second sprints on a steep incline of approximately six percent. If you don't know what a six-percent gradient looks or feels like, get on a treadmill and adjust the incline to six percent. Then find a hill that matches it.
Your first session will stimulate physiological adaptations that serve to better protect your muscles and connective tissues from damage in your next session. Known to exercise scientists as the "repeated bout effect," these adaptations occur very quickly. If you do your first steep hill sprints on a Monday, you will be ready to do another session by Thursday—and you will almost certainly experience less muscle soreness after this second session.
More: What Causes Muscle Soreness? Thanks to the repeated bout effect, you can increase your steep hill sprint training fairly rapidly and thereby develop strength and stride power quickly. First, increase the number of eight-second sprints you perform by two per session per week. Once you're doing eight to 10 sprints, move to 10-second sprints and a steeper, eight-percent hill. After a few more weeks, advance to 12-second sprints on a 10-percent hill. Always allow yourself the opportunity to recovery fully between individual sprints within a session. In other words, rest long enough so that you are able to cover just as much distance in the next sprint as you did in the previous one. Simply walking back down the hill you just ran up should do the trick, but if you need more time, take it.
Most runners will achieve as much strength and power improvement as they can get by doing 10 to 12 hill sprints of 12 seconds each, twice a week. Once you have reached this level and have stopped gaining strength and power, you can cut back to one set of 10 to 12 hill sprints per week. This level of maximum power training will suffice to maintain your gains through the remainder of the training cycle.
More: Power-Training for Distance Runners Sign up for your next race.